This invention relates to a hydraulic torque impulse generator of the type comprising a motor-rotated drive member including a hydraulic fluid chamber of a generally cylindrical shape, an output spindle having an impulse receiving rear portion extending into said fluid chamber through an opening in the forward end wall of the latter, a seal means associated with said drive member and said impulse receiving portion of said output spindle and arranged to divide said fluid chamber into at least one high pressure compartment and at least one low pressure compartment during a limited portion of the relative rotation between said drive member and said output spindle, and a seal barrier between said output spindle and said drive member for sealing off said fluid chamber from the atmosphere.
A problem concerned with hydraulic impulse generators of the above type is to accomplish an efficient fluid seal or barrier around the output spindle, a seal means which is able to withstand the very high pressure peaks generated in the fluid chamber during operation of the tool as well as the pressure fluctuations owing to temperature related volume changes in the hydraulic fluid.
The main object of the present invention is to accomplish a torque impulse generator of the above related type in which an improved fluid tight seal barrier is employed between the fluid chamber end wall and the output spindle, a seal barrier which is able to absorb temperature related volume changes in the hydraulic fluid and to ensure a substantially constant nominal pressure within the fluid chamber.
Further objects and advantages of the invention will appear from the following detailed description.